Diane Seward has been using fission-track analysis on apatite and zircon applied to many different aspects of geology with particular emphasis on basin evolution and tectonics. The method is suitable for understanding the paleotemperature histories of the upper crust in the temperature range from about 260 to 60°C. This temperature regime comprises the upper 8 km of the crust. By combining this method with (U-Th)/He studies on apatites the temperature range is now as low as 40°C. The applications are wide and varied.

The major rivers in Asia have been controlled by the tectonic and structural geology of the continent. Many of them flow along sutures ranging from in age from Carboniferous to Tertiary. They are very old. Since the early 20th century, these systems have also been the focal point of numerous river capture studies. Using thermochronological tools, fission-track analysis in particular, we have been able to develop some ideas about the timing of the change in the paths of two of these rivers.

The Tsangpo flows eastwards along the Tertiary suture and by combining fission-track ages with the structural geology we have been able understand the timing and reason for the development of the extremely deep gorge, where the river cuts through the Namche Barwa mountains.

The Changjiang (Yangtze) flows from Tibet and exits into the ocean at Shanghai. The river probably flowed originally southwards and was part of the Red River system. Again, using fission-track and (U-Th)/He ages on apatites in the Sechuan Basin and the Three Gorges, we suggest that the river may have changed direction at about 40 Ma. This is an on-going project and further studies are underway.